High-level Composition of QoS-aware Grid Workflows: An Approach that

Considers Location Affinity

Ivona Brandic, Sabri Pllana, Siegfried Benkner

Institute of Scientific Computing (ISC)University of Vienna

Austria

The Workshop on Workflows in Support of Large-Scale Science (works06) In conjunction with HPDC 2006, June 20, Paris, France

Ivona Brandic works06, HPDC06

ProjectInvolvement

Quasi-real time neurosurgery support

Maxillo-facial surgery support

Radiosurgery: Neurosurgery support

Inhaled drug delivery simulation

Advanced Models, Applications and Software Systems for High Performance Computing

http://www.vcpc.univie.ac.at/aurora

http://www.gemss.de/

Ivona Brandic works06, HPDC06

MotivationCT image

reconstruction

Maxillo facial surgery simulation

QoS specification:time, price

maxTime = 5 hprice = 20 €

Quasi-real time neurosurgery support

Ivona Brandic works06, HPDC06

MotivationQoS specification:time, price

maxTime = 5 hprice = 20 €

Legal and securityaspects: „Location affinity“

CT image reconstruction

Quasi-real time neurosurgery support

Maxillo facial surgery simulation

Ivona Brandic works06, HPDC06

Outline

• BPEL extensions for the specification of „location affinity“ (QoWL)

• Use cases for „location affinity“• UML-based Domain Specific Language (DSL) for QoS-

aware Grid workflows• System architecture• Case study• Conclusion

Ivona Brandic works06, HPDC06

QoWL Code Example

<qowl-element name=„activityName“ portType=„...“ wsdl=„...“ ...> ... <qos-constraints reqDescVar=„...“ ...> <qos-constraint name=„beginTime“ value=„...“ weight=„...“ /> <qos-constraint name=„endTime“ value=„...“ weight=„...“ /> <qos-constraint name=„price“ value=„...“ weight=„...“ /> <qos-constraint name=„geographicAffinity“ value=„...“ /> <qos-constraint name=„gridSiteAffinity“ value=„...“ /> ... </qos-constraints></qowl-element>

any QoWL element

QoS extension of a BPEL element

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Types of Location Affinity

• Grid site - gridSiteAffinity– Security, law, performance reasons

• Organisation - organisationAffinity– Hide business information from competitors– Sensitive business data

• Geographical region - geograficAffinity– Legal requirements – Electronic transfer of medical data – Medical studies including demographic data

Ivona Brandic works06, HPDC06

Specification of Location Affinity

A1

A2

A3

A4

A6

A5

A7

A8

A9

A10 A11

A12

A13

A14

A15

G1

G2

G3

<qowl-element name=„A3“ ...> ... <qos-constraints ...> <qos-constraint name=„gridSiteAffinity“ value=„SID“/> </qos-constraints></qowl-element>

<qowl-element name=„A11“ ...> ... <qos-constraints ...> <qos-constraint name=„geographicAffinity“ value=„GID“/> </qos-constraints></qowl-element>

<qowl-element name=„A7“ ...> ... <qos-constraints ...> <qos-constraint name=„organisationAffinity“ value=„OID“/> </qos-constraints></qowl-element>

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UML Modeling of QoS-aware Grid Workflows

• XML based workflow specification – error-prone and difficult for end users– Improvement by using a visual and intuitive modeling

language e.g. UML• High level modeling based on UML

– Activity diagrams– Visual modeling of QoS-aware Grid workflows– UML extensions mechanisms – Stereotypes and tagged values– UML based Domain Specific Language (DSL)

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Customizing UML for Modeling of QoS-aware Grid Workflows

<<metaclass>>Action

<<stereotype>>Invoke

portType: Stringwsdl: Stringoperation: StringinputVar: StringoutputVar: StringqosConstraints: QTypes

<<invoke>>Start

{ portType = appex wsdl = http://bridge:9355/SPECT/appex?wsdl operation = start inputVar = startRequest qosConstraints= qti:QTypes }

Definition of DSL e.g. Invoke Element

Usage of Invoke Element

UML based modeling of QoS-aware Grid workflows

A1 A2

A3 A4

„plain“ UML

Start

<<invoke>>Start

Stereotype Base Class Tags Description

Process «Process»

Activity qosConstraints:QType,variables:VType

Indicates that Activity represents a workflow process

Invoke«Invoke»

Action qosConstraints:QType,portType:String,operation:String,inputVar:String,outputVar:String,wsdl:String

Indicates that Action represents the operationInvocation of an external Grid Service

Copy«Copy»

Action From:FromTypeTo:ToType

Indicates that Action represents the data valueassignment

Sequence«Sequence»

SequenceNode qosConstraints:QType Indicates that SequenceNode represents a series ofactions which are executed sequentially

Flow«Flow»

StructuredActivityNode qosConstraints:QType Indicates that SequenceNode represents a set of Actions which may be executed concurrently

Receive«Receive»

AcceptEventAction portType:String,operation:String,variable:Stringwsdl:String

Indicates that AcceptEventAction represents a blocking message receive

Reply«Reply»

SendSignalAction portType:String,operation:String,variable:Stringwsdl:String

Indicates that SendSignalAction represents the replymessage to a message that was received through a«Receive»

Switch«Switch»

DecisionNode qosConstraints:QType Indicates that DecisionNode represents the conditionalexecution

While«While»

LoopNode condition:Boolean Indicates that LoopNode represents a while loop. Theloop body is executed until the condition is violated.

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QoWL Representation with the UML-based DSL (I)

A1 A2

<<Switch>>SampleSwitch

<<Switch>>SampleSwitch

{qosConstraints = qtiQTypes}

Aggregation function <<Switch>>:

time = Max {time(Bi)| i=1,..,k}price = Max {price(Bi)| i=1,..,k}

Switch

[case condition] [otherwise]

A1

<<Process>>SampleProcess

<<Process>>SampleProcess

{qosConstraints = qtiQTypes}

Process

Ivona Brandic works06, HPDC06

A1

A2

A3

<<Sequence>>SampleSequence

<<Sequence>>SampleSequence

{qosConstraints = qtiQTypes}

<<Sequence>> Aggregation function:

time = ∑ time(Ai)i=1

n

price = ∑ price(Ai)i=1

n

A1 A2

<<Flow>>SampleFlow

<<Flow>>SampleFlow

{qosConstraints = qtiQTypes}

<<Flow>> Aggregation function:

time = Max {time(Ai)| i=1,..,n}price = ∑ price(Ai)

i=1

n

Sequence Flow

QoWL Representation with the UML-based DSL (II)

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QoS-aware Grid Workflow System

QoS-aware Grid Workflow Engine (QWE)

XML parser / unparser

QoSNegotiator

QoSExecuter

WF Planner(static/dynamic)

Service Deployerand Generator

Grid Infrastructure

Tomcat Apache AXIS

QoS-awareVGE Services

Service 1 Service n...

nonVGE Services

Service 1 Service n...

Teuta

GUI

ModelTraverser

ModelChecker

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Specification of MFSS Workflow

Ivona Brandic works06, HPDC06

Generated MFSS Code<sequence name="FEM_Sequence">... <copy name="CID"> <from part=“CID" variable=“getCIDRequest"/> <to part=“CID" variable=“uploadOperation"/> </copy> ... <invoke inputVar="CID" name="StartOperation" operation="start" portType="ApplicationExecutor"> <qos-constraints ReqDesc="maxilloReqDescVar"> <registry wsdl="http://gescher.univie.ac.at:9357/registry/reg?wsdl"/> <registry wsdl="http://kim.univie.ac.at:9357/registry/reg?wsdl"/> <registry wsdl="http://aurora.tuwien.ac.at:9357/registry/reg?wsdl"/> <qos-constraint name="beginTime" value="2006-02-02T16:00:00.000+02:00“ weight="0.3"/> <qos-constraint name="endTime" value="2006-02-02T18:00:00.000+02:00"/> <qos-constraint name="price" value="15" weight="0.7"/> <qos-constraint name="geographicAffinity" value="AT"/> </qos-constraints> </invoke> <invoke name="DownloadOperation“ ... /> ... </sequence>

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Related Work• Languages

– BPEL – GPEL– GSFL– SWFL– WSFL– (X)Scufl– AGWL– …

• Projects– BioOpera– Chimera– DAGMan– DiscoveryNet– FreeFluo– Grid ANT– Gridbus– JOpera– Kepler– LEAD– Pegaus– Taverna– Teuta– Triana– …

Ivona Brandic works06, HPDC06

Conclusion and Future Work• Workflow execution should meet users requirements

– Developed QoS extensions for BPEL– Developed the concept of „location affinity“– Performance, economical, security and legal QoS

• Simplification of workflow specification– Based on UML standard– Developed DSL for QoS-aware Grid workflows

• Validation through specification of a real world workflow• Future work

– Optimization and adaptivity issues